Spine
Back pain is an extremely common
symptom and the spine is one of the areas most frequently imaged
with MRI. MRI beautifully demonstrates the anatomical components of
the spine and their relationships.
The whole spine can be subdivided into its component
parts - cervical spine(neck), thoracic spine(chest level), lumbar
spine & sacrum(lower spine). These are anatomically different
areas with a separate structure and function.
There are several functions of the spine - support
& mobility and it also contains the spinal cord. The spinal
cord is a communication highway that carries electrical messages
between the brain and the peripheral parts of the body. It is
protected by a bony spinal canal. Nerves travel from the spinal
cord to the peripheral parts of the body. Pressure on either the
spinal cord or the related nerves can cause pain, tingling,
weakness or sensory alteration like numbness.
The mechanical strength of the spine is provided by the
bony vertebral bodies and the intervertebral discs which separate
them. The functions of the disc include cushioning, mechanical
strength and flexibility. The spinal column is further strengthened
by ligaments which attach to the bony vertebrae.
Normal Lumbar Spine
All the discs return normal
signal and disc height is maintained throughout.
Disc Prolapse ''Slipped
Disc''
Disc bulging or prolapse is a
frequent finding. This can occur at any level but is most
frequently seen in the lumbar spine. Disc bulging or prolapse can
vary in size, shape and position. Depending on the position of a
disc prolapse different symptoms may result. If a disc prolapse is
pressing on a spinal nerve there may be pain or altered sensations
which radiates through the buttock, down the leg or into the calf
or foot.
Symptoms
Pain (which may start suddenly), sensory changes -
tingling , numbness which can radiate down the leg. Immobility.
MRI
The
disc arrowed is bulging & pressing on the spinal nerve. Lumbar
disc prolapse
Degenerative
Changes
Low back pain can be caused by
a variety of abnormalities. One of the most common findings is
degenerative change(wear & tear). We are living longer and
longer and combined with a physical lifestyle this can take its
toll on the intervertebral discs, joints and ligaments in the
spine. Symptoms: Pain, stiffness.
MRI
Narrowed disc spaces,
small bony ''osteophytes'' arising from the vertebrae. Degenerative
Changes in Lumbar spine
Spinal Infection
MRI can help diagnose spinal
infection - the clinical symptoms of spinal infection can mimic
other causes of back pain. An early diagnosis is important as the
treatment for this condition requires antibiotics and often
hospital admission. Infection commonly affects the disc and is
therefore called 'discitis'.
Symptoms
Pain. Non specific symptoms
of infection - fever, sweats, unwell.
MRI
Different sequences can be used
such as T1, STIR (a sensitive but non specific marker of
abnormality) and contrast enhanced images.
The
case shows spinal infection in the L1-L2 intervertebral disc.
Figure 1 - T1 weighted image. Infection in the
L1-L2 disc space
Figure 2 - Gadolinium
contrast enhanced image. Enhancement of the L1-L2 disc and
surrounding tissues.
Figure 3 - STIR image.
Disc narrowing & fluid next to the disc. The STIR sequence is a
very sensitive but non specific indicator of abnormality.
Case studies:
